This invention relates to an electric two motor drive. More particularly, it relates to the construction of a stator for use in a motor having the field winding of a commutator motor with a small number of poles, two at least, and the stator winding, distributed in slots, of an induction motor with a larger number of poles, and in which both windings are arranged on a common lamination stack.
In one electric two motor drive of this type (See German Offenlegungsschrift No. 25 30 294), 36 slots are arranged uniformly, but with unequal slot cross section, over the inner circumference of the stator lamination stack and the winding of the induction motor is uniformly distributed in all the slots; the winding of the series motor occupies some of the slots, and these only partially. For this purpose, the slots in this region have larger slot cross sections than those other slots which are occupied by the winding of the induction motor alone. Both windings are arranged so that the sides of all coils run axially through the slots with the coils being interconnected at the end faces, forming coil heads in front of either the stator lamination stack or the rotor bore space where there is no shaft.
In another two motor drive (See German Offenlegungsschrift No. 25 01 300) which has a multiple-pole induction motor winding and a two-pole commutator motor winding insulated therefrom, the stator lamination stack is provided with discrete main poles on its inner circumference around which the field winding of the commutator motor part is arranged, while the stator winding of the induction motor part is accommodated in slots under the pole pieces of the main poles.
It is an object of the present invention to reduce the cost of fabricating and, in particular, of winding the stator of an electric two motor drive of the type mentioned above.